焊接电流对挤压态AZ71镁合金TIG焊接头组织的影响
Effect of Current Intensity on Microstructure of TIG Welded Joint of AZ71 Alloy
武婧亭1， 游国强1,2， 郭强1， 龙思远1,2
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作者单位：（1.重庆大学 材料科学与工程学院，重庆 400030；2.国家镁合金材料工程技术研究中心,重庆 400030）
中文关键字： AZ71镁合金； TIG焊； 显微组织； 焊接接头； 焊缝区
英文关键字：AZ71; TIG; microstructure; welded joint; weld zone
中文摘要： 对2.2 mm厚挤压态AZ71镁合金板材进行交流TIG焊研究，焊接电流分别取70、80和90 A。结果表明：电流为90A时，焊缝外观成形良好，无宏观缺陷，焊缝达到熔透状态。用光学显微镜、SEM、EDS等对焊缝的微观组织进行观察分析表明：随着电流的增加，焊缝区和热影响区组织逐渐粗化，热影响区宽度增加。电流的增加还导致焊缝区晶界上β-Mg17Al12相逐渐增多，形态也发生了变化。
英文摘要：Tungsten inert-gas(TIG) welding process was adopted to join hot-extruded AZ71 profile with 2.2 mm thickness. The current intensity was 70 A, 80 A and 90 A, respectively. The results show that when the current reaches 90 A, the deformation of weld is good without macro defects and the weld is penetrated. The microstructure of the weld is analysed by optical microscope, SEM and EDS. The research indicates that with the increase of current, the grains in weld zone and heat-affected zone become coarser, the width of heat-affected zone increases. At the same time, the increased current results in the increase of β-Mg17Al12 and the shape of β-Mg17Al12 varies with the current intensity.